ABSTRACT
Objective:To investigate whether microRNA-21-5p (miR-21-5p) alleviates hyperoxia-induced acute lung injury (HALI) through activating the phosphatidylinositol 3 kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathway by regulating apoptosis of type Ⅱ alveolar epithelial cell (AECⅡ).Methods:Seventy-two male Sprague-Dawley (SD) rats were divided into normozone-controlled group, HALI group, PI3K/Akt signaling pathway inhibitor LY294002+HALI group (LY+HALI group), miR-21-5p overexpression+LY294002+HALI group (miR-21-5p+LY+HALI group), miR-21-5p overexpression+HALI group (miR-21-5p+HALI group), and dimethyl sulfoxide (DMSO)+HALI group by random number table method with 12 rats in each group. Animal models of HALI were prepared using 95% concentrations of oxygen. The animals in the normozone-controlled group were fed normally under normoxia. Transfection of lung tissue by miR-21-5p adeno-associated viral vector AAV6-miR-21-5p was performed by instillation of 200 μL titer (1×10 12 TU/mL) through a tracheal catheter 3 weeks prior to modeling. DMSO and LY294002 were administered via the tail vein at 0.3 mg/kg 1 hour before modeling. After 48 hours of modeling, carotid artery blood was collected to detect oxygenation index (OI) and respiratory index (RI), and real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect miR-21-5p expression. Lung tissue was collected, and the levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukins (IL-6, IL-1β) were measured by enzyme-linked immunosorbent assay (ELISA), and the ratio of pulmonary wet/dry weight (W/D) was determined, and the pathological changes of lung histopathology were observed under the light microscopy after hematoxylin-eosin (HE) staining. Each group was purified AECⅡ cells from 6 rats, the apoptosis rate was detected by flow cytometry, and the expression levels of phosphatase and tensin homologous gene (PTEN), and proteins from the PI3K/Akt signaling pathway were detected by Western blotting. Results:Compared with the normozone-controlled group, alveolar septal thickening and massive inflammatory cell infiltration were found after hyperoxia exposure, RI, inflammatory factors, lung W/D ratio, pathological score, AECⅡ cells early apoptosis rate, PTEN protein expression and phosphorylation level of Akt were increased, while OI and miR-21-5p expression were decreased, indicating the successful preparation of the model. After pretreatment, LY294002 could aggravate the pathological injury of lung tissue in HALI rats, RI, inflammatory factors and lung W/D ratio were further increased, and OI was further reduced compared with HALI group. At the same time, it could promote the AECⅡ cell apoptosis, further up-regulate the expression of PTEN, and reduce the phosphorylation of Akt. However, miR-21-5p pretreatment could negatively regulate PTEN, activate PI3K/Akt signal pathway, inhibit AECⅡ cell apoptosis, and reduce HALI, which was shown by the decreased level of inflammatory factors in miR-21-5p+LY+HALI group compared with LY+HALI group [TNF-α (μg/L): 100.33±3.48 vs. 116.55±2.53, IL-6 (ng/L): 141.06±3.70 vs. 161.31±3.59, IL-1β (μg/L): 90.82±3.69 vs. 112.23±2.87, all P < 0.05], RI, lung injury pathology score, lung W/D ratio, and AECⅡ cell early apoptosis rate were significantly decreased [RI: 0.81±0.02 vs. 1.05±0.07, pathology score: 0.304±0.008 vs. 0.359±0.007, lung W/D ratio: 5.29±0.03 vs. 5.52±0.08, apoptosis rate: (27.20±2.34)% vs. (34.17±1.49)%, all P < 0.05], OI and expressions of miR-21-5p were significantly increased [OI (mmHg, 1 mmHg≈0.133 kPa): 266.71±2.75 vs. 230.12±4.04, miR-21-5p (2 -ΔΔCt): 2.21±0.13 vs. 0.33±0.03, both P < 0.05], and PTEN protein expression in AECⅡ cell was significantly reduced (PTEN/GAPDH: 0.50±0.06 vs. 0.93±0.06, P < 0.05), and phosphorylation level of Akt was significantly increased [phosphorylated Akt (p-Akt) protein (p-Akt/GAPDH): 0.86±0.05 vs. 0.56±0.06, P < 0.05]. Conclusion:miR-21-5p attenuates HALI by inhibiting AECⅡ cell apoptosis, possibly through negative regulation of PTEN to activate PI3K/Akt signaling pathway.
ABSTRACT
OBJECTIVES@#To explore the molecular mechanism for thyroid cancer metastasis via analyzing the role of microRNA (miR)-21-5p and its target gene recombinant sclerostin domain containing protein 1 (SOSTDC1) in thyroid cancer.@*METHODS@#The target miR-21-5p was screened through bioinformatics analysis and cell verification, and the thyroid cancer cell lines was transfected with miR-21-5p inhibitor. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, flow cytometry, and cell scratch test were used to detect the proliferation, apoptosis and migration of thyroid cancer cells in the miR-21-5p inhibitor group and the inhibitor control group, respectively. The luciferase report experiment was used to verify the relationship between miR-21-5p and SOSTDC1, Western blotting was used to detect the expression levels and phosphorylation levels of SOSTDC1,phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and mitogen-activated protein kinases (MAPK), extracellular regulated protein kinases (ERK) in thyroid cancer cells.@*RESULTS@#MiR-21-5p was significantly increased in thyroid cancer cells,which was negatively correlated with SOSTDC1 (@*CONCLUSIONS@#MiR-21-5p in thyroid cancer cells can target the expression of SOSTDC1 and affect the activities of PI3K/Akt and MAPK/ERK, thereby inhibiting the apoptosis of thyroid cancer cells and promoting cell proliferation and migration.
Subject(s)
Humans , Adaptor Proteins, Signal Transducing , Apoptosis/genetics , Cell Line, Tumor , Cell Movement , Cell Proliferation , MicroRNAs/genetics , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Thyroid Neoplasms/geneticsABSTRACT
To investigate the effect of overexpression of microRNA-21-5p (miR-21-5p) on early apoptosis of type Ⅱalveolar epithelial cells (AECⅡ) in rats with hyperoxic acute lung injury (HALI). Methods The Sprague-Dawley (SD) rats were randomly divided into four groups: control group (CON group), hyperoxia group (H group), overexpression group (OE group) and empty vector group (EV group), with 20 rats in each group. HALI animal model was made by inhaling high concentration oxygen (oxygen concentration ≥90%); CON group was arranged to inhale room air. The miR-21-5p adeno-associated virus-6 (AAV-6) overexpression vectors or empty vectors were dripped into the lungs of OE group and EV group through tracheal tube, respectively. The hyperoxia model was prepared after 3 weeks of feeding. At 0, 24, 48 and 60 hours after making model, 5 rats were selected to detect lung injury parameters:oxygenation index (OI), respiratory index (RI), wet/dry ratio (W/D), pathological injury score of lung tissue; real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-21-5p in AECⅡ, and flow cytometry was used to detect the early apoptotic rate of AECⅡ. Results ① The lung injury parameters: in H group, the OI gradually decreased with time, but the RI, lung W/D ratio and pathological score increased gradually with time, the difference between CON group was statistically significant at 24 hours [OI (mmHg, 1 mmHg = 0.133 kPa):336.04±5.79 vs. 400.22±19.70, RI: 0.20±0.02 vs. 0.10±0.06, lung W/D ratio: 5.04±0.09 vs. 4.85±0.09, lung tissue pathological score: 0.13±0.01 vs. 0.07±0.01, all P < 0.05]. It indicated that HALI model could be successfully established by inhaling high concentration oxygen continuously. ② The expression of miR-21-5p: the miR-21-5p was gradually increased in H, OE and EV groups, and the expression of miR-21-5p was significantly higher than that in CON group at 24, 48 and 60 hours. Compared with H group, the expression of miR-21-5p was significantly increased further in OE group at 0, 24, 48 and 60 hours (2-ΔΔCt: 3.75±0.11 vs. 0.98±0.14, 3.98±0.12 vs. 1.18±0.13, 4.28±0.18 vs. 1.49±0.06, 4.66±0.12 vs. 1.80±0.12, all P < 0.05). ③ The early apoptosis of AECⅡ: the early apoptosis rate gradually increased with time in H, OE and EV groups, and the early apoptosis of AECⅡ was significantly higher than that in CON group at 24, 48 and 60 hours. Compared with H group, the early apoptosis rate was significantly decreased in OE group at 24, 48 and 60 hours [(1.22±0.63)% vs. (2.84±0.59)%, (5.76±0.18)% vs. (13.10±2.01)%, (29.48±0.48)% vs. (49.04±1.36)%, all P < 0.05]. ④ There was no significant difference in the expression of miR-21-5p and the early apoptosis of AECⅡ cells between EV group and H group at each time point. Conclusion Overexpression of miR-21-5p could inhibit the early apoptosis of AECⅡ in rats with HALI.
ABSTRACT
Objective To verify the targeting regulatory relationship between microRNA (miR)-21-5p and mitogen-activated protein kinase kinase 3 (MKK3).Methods miR-21-5p and MKK3 targeted relationship was analyzed by bioinformatics database predict.Constructing MKK3 3'UTR reporter vector (MKK3-3U) and mutation reporter vector (MKK3-3 U-M) was constructed by synthesizing miR-21-5p mimics (mimic),miR-2 1-5p inhibitor (inhibitor),nonsense miR (NC).NC (NC1 group),mimics (mimic1 group),inhibitor (inhibitor1 group) together with MKK3-3U cotransfected human embryonic kidney (HEK293) cells,respectively.Empty vector-pYr-MirTarget (NC2 group),MKK33U (Mt group),M KK3-3U-M (Mut group) together with mimic co-transfected HEK293,respectively.The fluorescence ratio was detected by dual luciferase assay.NC,mimics,inhibitor intervened human renal tubular epithelial (HK-2) cells,respectively.RT-PCR and Western blot were used to test cell MKK3 expression level in HK-2.Results 1.The fluorescence ratios of NC1 group,mimicsl group,and inhibitor1 group were 100.00％,67.99％,133.17％,and there was difference between mimic1 group and NC1 group(t =19.93,P ＜ 0.05).2.The fluorescence ratios of NC2 group,Mt group and Mut group were 100.00％,65.30％,98.48％,and there was difference between Mt group and NC2 group (t =14.39,P ＜ 0.05).There was no significant difference between NC2 and Mut group (t =0.63,P ＞ 0.05).3.MKK3 mRNA relative expression levels of the control group mimic2 group and inhibitor2 group were 1.36 ± 0.02,1.01 ± 0.04,1.43 ± 0.06 ; relative protein expression levels were 0.97 ± 0.05,0.62 ± 0.06,1.36 ± 0.32.MKK3 mRNA and protein levels of mimic2 group were significantly lower compared with the control group (F =85.98,118.26,all P ＜ 0.01).Conclusions MKK3 is the target gene of miR-21-5p.miR-21-5p can regulate the expression of MKK3 both in mRNA and protein levels.miR-21-5p may be an important regulatory molecule in p38 mitogen-activated protein kinase signaling pathway.